The present invention concerns a machine for heat treating through remelting the surface of cams carried by a camshaft.
It is known that the remelting is a heat treatment method which consists in forming a localized fusion on a surface, such as a cam surface, with an electric arc surrounded by an inert gas jet and produced by a torch. A "quenching" or hardening of the cam surface is thus obtained, which surface is generally scanned by the electric arc in such a manner that the treatment is carried out over the whole surface to be treated.
More precisely, according for example to the document U.S. Pat. No. 4,312,685, camshaft remelting machines are known in which a vertical movement of the torch is performed with the aid of a main cam so that the torch is at a constant distance from the surface to be treated, the camshaft itself being actuated in a rotation movement combined with an axial translation movement in order to perform the scanning.
Such a machine presents drawbacks resulting in particular from the fact that the point of impact of the torch is generally located on an inclined surface of the cam in particular when the latter has a pointed top, and it follows from the foregoing that the electric arc of the torch forms a recess or a cavity on the cam surface, since the molten metal flows as a result of the tilting of said surface. In other words, after the remelting treatment, a cam surface is obtained which is inappropriate for the utilization and which necessitates an important reprocessing.